Evaluation of the effect of lichens on ceramic roofing tiles by scanning electron microscopy and energy-dispersive spectroscopy analyses

The effect of the actions of some lichens on the quality of ceramic roofing tiles was investigated in view of textural and microstructural changes considering their biocorrosion resistance. Two types (extruded and pressed) of the real ceramic roofing tiles aged 6 to 10 years, as well as the ceramic model systems formed with the additives of the specific chemical composition Cu-slag powder (10 wt%) and CuO powder (1 wt%), treated with various concentrations of oxalic acid (0.01 wt%, 0.1 wt%, and 4 wt%) were investigated. The thalli of lichen (Verrucaria nigrescens) growth on ceramic roofing tile were examined by scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). Investigation by SEM and EDS gave information regarding the ultrastructure characteristics of the thallus and the lichen-ceramic tile contact zone, allowing the observation of the hyphal penetration and filling up of the fissures and cracks by the lichens' hyphae. The CuO as the raw mixture additive changed the quality of the surface of the ceramic model systems as it has increased resistance to oxalic acid actions. The textural changes in the ceramic model systems and the formation of the identified destructive crystal phase, whewellite, were slowed down. The fundamental interactions between lichens and ceramic materials of the model systems have been identified as physico-chemical processes based on oxalic acid actions, which could cause ceramic matrix deterioration and consequently aging of ceramic roofing tile systems.     

Comparison of the semantic networks in patients with dementia and amnesia.

The semantic networks of 13 patients with Alzheimer's disease (AD), 13 patients with Huntington's disease (HD), 8 amnesic (AM) patients, and 26 controls were generated by multidimensional scaling and Pathfinder analyses of their responses on a triadic comparison task. The semantic networks of HD and AM patients were essentially normal, whereas the networks of AD patients were deviant in a number of ways. The AD patients' networks were dominated by a different dimension, had fewer common links, and consisted of associations of atypical strength. These results suggest that structural alteration of semantic networks is characteristic of Alzheimer's disease and is not evident in all forms of dementia and amnesic conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Integration of impulsivity and positive mood to predict risky behavior: Development and validation of a measure of positive urgency.

In 3 studies, the authors developed and began to validate a measure of the propensity to act rashly in response to positive affective states (positive urgency). In Study 1, they developed a content-valid 14-item scale, showed that the measure was unidimensional, and showed that positive urgency was distinct from impulsivity-like constructs identified in 2 models of impulsive behavior. In Study 2, they showed that positive urgency explained variance in risky behavior not explained by measures of other impulsivity-like constructs, differentially explained positive mood-based risky behavior, differentiated individuals at risk for problem gambling from those not at risk, and interacted with drinking motives and expectancies as predicted to explain problem drinking behavior. In Study 3, they confirmed the hypothesis that positive urgency differentiated alcoholics from both eating-disordered and control individuals. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The use of nickel oxide as a hole transport material in perovskite solar cell configuration: Achieving a high performance and stable device

Solar cells incorporated with organic-inorganic lead or tin halide-based perovskite materials as active light-absorber surfaces are referred to as perovskite solar cells (PSCs). This fast advancing solar technology has recorded an increase in its efficiency from 3.8% in 2009 to above 25% in recent years. The technology creates room for diverse device architectures, which enhances further development of thin-film solar cells and photovoltaics. This article reviews the use of nanocrystalline nickel oxide (NiO) film as a hole transport material in PSCs. The literature on pure nickel oxide and doped nickel oxide films has been discussed. The principle of operation, charge separation of PSCs and the various parameters that affect the efficient hole transport mechanisms, power conversion efficiency, growth mechanism, and stability of PSCs have also been discussed. Possible electron-blocking applications and future perspective of nickel oxide films have also been discussed.     

Cell entry of one-dimensional nanomaterials occurs by tip recognition and rotation

Materials with high aspect ratio, such as carbon nanotubes and asbestos fibres, have been shown to cause length-dependent toxicity in certain cells because these long materials prevent complete ingestion and this frustrates the cell. Biophysical models have been proposed to explain how spheres and elliptical nanostructures enter cells, but one-dimensional nanomaterials have not been examined. Here, we show experimentally and theoretically that cylindrical one-dimensional nanomaterials such as carbon nanotubes enter cells through the tip first. For nanotubes with end caps or carbon shells at their tips, uptake involves tip recognition through receptor binding, rotation that is driven by asymmetric elastic strain at the tube-bilayer interface, and near-vertical entry. The precise angle of entry is governed by the relative timescales for tube rotation and receptor diffusion. Nanotubes without caps or shells on their tips show a different mode of membrane interaction, posing an interesting question as to whether modifying the tips of tubes may help avoid frustrated uptake by cells.     

Effect of preparation method on the glycaemic index of novel potato clones

The purpose of this study was to investigate whether the effects of cooling and reheating on the glycaemic index (GI) of novel potato clones (selections) differed depending on selection and whether cooling altered starch absorption in vivo. We conducted 3 experiments using 4 novel potato clones in healthy subjects. Experiment 1: the GI of 4 selections each prepared in 3 ways (freshly boiled, cooled, or cooled and reheated) was measured in 2 groups of 10 subjects (each group tested 2 selections). Experiment 2 (n=10): two selections from Experiment 1 were re-tested one year later, by a different subject group. Experiment 3 (n=10): two selections from Experiment 1 were tested by subjects from Experiment 2 to assess the rate and extent of starch absorption using the second-meal effect and the breath hydrogen method, respectively. Experiment 1 demonstrated a selection×treatment interaction for GI (p=0.024); cooling reduced the GI of two selections by 40-50% (p<0.05) but reduced GI of the other 2 by only 8-10% (ns). Experiment 2 confirmed the selection×treatment interaction (p=0.018) seen in Experiment 1. Experiment 3: cooling reduced the GI by an average of 37% (p<0.05) but only increased starch malabsorption in vivo from 3% to 5% (p=0.021); there was no significant second-meal effect. It is concluded that the effect of cooling on the GI of potatoes may vary from 0-50% depending on selection. However, the mechanism for the effect is not clear: the 2% increase in starch malabsorption seen upon cooling potatoes was not nearly enough to account for the 37% reduction in GI.     

Effects of gallotannin treatment on attachment, growth, and survival of Escherichia coli O157:H7 and Listeria monocytogenes on spinach and lettuce

Food-borne illness outbreaks are increasingly associated with fresh produce. Their high prevalence may reflect the lack of methods to effectively remove pathogenic bacteria from the surface of fruits and vegetables. This study evaluated the effect of antimicrobial gallotannins on attachment, growth, and survival of food-borne pathogens on green leafy vegetables. Spinach leaves and interior leaves of lettuce harboring high and low cell counts of background microbiota, respectively, were washed with tap water with and without added gallotannins. To account for the variability among organisms, green leafy vegetables were inoculated with strain cocktails of Escherichia coli O157:H7 and Listeria monocytogenes. Cell counts of L. monocytogenes were significantly reduced by the gallotannin treatment. Lower cell counts after storage for 8?days at 4?°C demonstrated antimicrobial effects of gallotannins retained on the surface of green leafy vegetables. Gallotannin treatments with 1?g/L did not inhibit E. coli O157:H7 but hindered their attachment to filter paper by up to 94?%. The addition of gallotannin-containing extracts from mango (Mangifera indica L.) kernels to the washing water did neither alter color nor texture of bagged fresh-cut products. In conclusion, gallotannin treatment significantly reduced surface contamination of green leafy vegetables with L. monocytogenes and reduced the attachment of cells of E. coli O157:H7.     

Differential effects of resveratrol and its naturally occurring methylether analogs on cell cycle and apoptosis in human androgen‐responsive LNCaP cancer cells

Stilbenes are phytoalexins that become activated when plants are stressed. These compounds exist in foods and are widely consumed. Resveratrol is a grape‐derived stilbene, which possesses a wide range of health‐promoting activities, including anticancer properties. Several other stilbenes structurally similar to resveratrol are also available in food, but their biological activities remain largely unknown. In this study, we compared the effects of resveratrol and its natural derivatives pterostilbene, trans‐resveratrol trimethylether, trans‐pinostilbene and trans‐desoxyrhapontigenin on androgen‐responsive human prostate cancer LNCaP cells. We found that these compounds exert differential effects on LNCaP cell growth, cell cycle and apoptosis. Trans‐resveratrol trimethylether appeared to be the most potent compound among the stilbenes tested. Treatment of LNCaP cells with trans‐resveratrol trimethylether resulted in G2/M blockage while other compounds, including resveratrol, induced G1/S arrest. Moreover, different from other compounds, trans‐resveratrol trimethylether induced apoptosis. At the molecular level, the effects of these compounds on cell cycle correlated with induction of the cyclin‐dependent kinase inhibitor 1A and B mRNA levels. Additionally, these compounds also inhibited both androgen‐ as well as estrogen‐mediated pathways. These results provide mechanistic information on how resveratrol and its methylether analogs may act to contribute to potential antiprostate cancer activity.     

Synthesis and Biological Evaluation of Fluorescent Bryostatin Analogues

To investigate the cellular distribution of tumor‐promoting vs. non‐tumor‐promoting bryostatin analogues, we synthesized fluorescently labeled variants of two bryostatin derivatives that have previously shown either phorbol ester‐like or bryostatin‐like biological activity in U937 leukemia cells. These new fluorescent analogues both displayed high affinity for protein kinase C (PKC) binding and retained the basic properties of the parent unlabeled compounds in U937 assays. The fluorescent compounds showed similar patterns of intracellular distribution in cells, however; this argues against an existing hypothesis that various patterns of intracellular distribution are responsible for differences in biological activity. Upon further characterization, the fluorescent compounds revealed a slow rate of cellular uptake; correspondingly, they showed reduced activity for cellular responses that were only transient upon treatment with phorbol ester or bryostatin 1.